With advances in computer and network technology, cloud video storage systems have been widely used, especially in the field of video surveillance. A cloud video storage system generally includes a client, a management server, a storage server, and a data forwarding server.
A playback of a video at a multiplied speed is often required in the cloud video storage system. In the related art, the video playback performed in the cloud video storage system generally includes the following operations:
a client requests a storage management server for the address of a data forwarding server;
the storage management server determines a data forwarding server, and sends the address of the data forwarding server to the client;
the client sends a video playback request to the data forwarding server;
upon receiving the video playback request, the data forwarding server obtains video data of the video to be played back from a storage server and buffers the obtained video data;
the client obtains the buffered video data from the data forwarding server and plays back the obtained data at a multiplied speed.
For a bit stream having a bit rate of 4 M, if the playback is performed at 8 times its normal speed in the way described above, a bandwidth of 4*8=32 (Mbps) is required. In addition, a video is often played back in multiple views. Therefore, the bandwidth has to be multiplied by the number of views of the playback. For example, if the number of views of the playback is 4, the required bandwidth is 4*8*4=128 (Mbps).
In practice, however, not all networks can provide a bandwidth of 128 Mbps, especially for a case where the client requiring the playback and the data forwarding server are not in a same network segment. In such a case, it is more difficult for a client in a handheld device under 3G/4G network to achieve a bandwidth of 128 Mbps. It can be seen that a video playback performed in the manner described above requires a high network bandwidth.